CVVD Engine Valve Timing Control via Intake-Only CVVT
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing engine systems with continuous variable valve duration (CVVD) and continuous variable valve timing (CVVT) devices face challenges in simultaneously controlling valve duration and timing effectively across varying engine speeds and loads, impacting fuel efficiency and power performance.
Innovation Solution
A system and method that classify engine control regions based on speed and load to optimize intake and exhaust valve timing and duration, using a combination of CVVD and CVVT devices, with a controller managing operations to apply maximum durations, control valve overlap, and adjust timing to maintain combustion stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a CVVD device and CVVT device are mounted on both intake and exhaust to simultaneously control valve duration and timing, then fuel efficiency and power performance are improved, but device complexity and production cost increase
Solution Approach 1:
The patent extracts the CVVT device from the exhaust side, keeping it only on the intake side. This removes the complex exhaust timing control mechanism while maintaining intake valve timing control, thereby reducing device complexity and production cost. The system achieves acceptable fuel efficiency and power performance without requiring exhaustive control on both sides.
Solution Approach 2:
The patent applies different control strategies to intake and exhaust valves based on their specific functional requirements. The intake valve receives both CVVD and CVVT control for optimal air-fuel mixture management, while the exhaust valve receives only CVVD control. This localized differentiation optimizes overall system performance while avoiding unnecessary complexity on the exhaust side.
2Power
If CVVD and CVVT devices are mounted on both intake and exhaust to control valve timing, then power performance under high load is enhanced, but manufacturing cost increases
Solution Approach 1:
The patent removes the exhaust CVVT device to reduce manufacturing cost. The system maintains power performance under high load conditions through optimized intake valve control using the CVVD and intake CVVT devices, eliminating the need for expensive dual-side exhaust timing control mechanisms.
3Reliability
If exhaust valve timing is controlled with CVVT device, then combustion stability is maintained, but device complexity increases
Solution Approach 1:
The patent removes the exhaust CVVT device while maintaining combustion stability through alternative means. The system uses the intake valve timing control and optimized exhaust valve duration control via CVVD to achieve stable combustion, eliminating the need for complex exhaust timing control hardware.
Data Source
AI summary
The present disclosure provides a system and a method for controlling valve timing of a continuous variable valve duration engine. The method may include: classifying a plurality of control regions depending on an engine speed and an engine load; applying a maximum duration to an intake valve and controlling a valve overlap between the intake valve and an exhaust valve in a first control region; maintaining the maximum duration of the intake valve and applying a maximum duration to the exhaust valve in a second control region; maintaining a manifold absolute pressure (MAP) at a predetermined pressure in a third control region; controlling a throttle valve to be fully opened and generating the valve overlap in a fourth control region; and controlling the throttle valve to be fully opened and controlling intake valve closing (IVC) timing according to the engine speed in a fifth control region.